Burner



D. VAN LAW Oct. 26, 1937.

BURNER Filed Feb. 15, 1932 -7- INVENTOR. 06M Um fw {rea/nde! @f IWW Ml lilll ATTORNEY Patented Oct. 26, 1937 UNITED STATLES PATENT OFFICEBURNER.

Durbin Van Law, Denver,- Colo., asslgnor, by mesne assignments, toPowderco Inc., Denver, Colo., a corporation of Colorado ApplicationFebruary 15, 1932, Serial No. 593,006

1o claims.

burner, for the initial ignition of fuel in a fuelcarrying air-currentprior to its entering the furnace.

Another object is to provide a burner, the component parts of which aredurable and heat-resisting, and assembled in a simple arrangement whichpermits of ready adjustments and replacement of parts.

Still another object is to provide a burner-unit having in associationwith a heat-resisting tip, an igniter for fuel in a fuel-carryingair-current fed to the tip, means to reduce the velocity of theair-current in the tip, and means for admitting auxiliary air to theigniter.

Further objects are to be found in details of construction and in noveland useful arrangements and combinations of parts as will be fully setforth in the course of the following description.

In the drawing, in which similar reference characters designatecorresponding parts throughout the views,

Figure 1 represents a sectional elevation of a burner-system inaccordance with the present invention,

Figure 2, a face-view of the burner, looking in the direction of thearrow A in Figure 1; and

Figure 3, a section taken on the line '3-3, Figure 1.

Referring further to the drawing, a preliminary combustion chamber 5 isfitted and secured in an opening of the furnace wall 6. 'I'hepreliminary combustion chamber which is made of heat-resisting material,such as fire-brick, has an opening aring in opposite directions from atransverse plane nearest the outer surface of the wall.

The shorter conical portion 'I of the opening provides a housing for thebody-part or tip of a burner-unit while the inner and longer conicalportion affu'nctlons for the ignition and diffusion of fuel infuel-carrying currents before they pass into the furnace. g

A face-plate 9 fastened upon the outer surface of the furnace-wall, hasa'n opening corresponding in size with that of the preliminarycombustion chamber at the extreme outer end thereof and fastened to theface-plate by means of studbolts I0, is a flanged ring I2 in which thebeforementioned tip or body-member of the burnerunit is supported.

'I'he kbody-member or burner tip consists of a b loekll of terra cottaor other vitreous clay product, positioned rearwardly of the preliminarycombustion chamber, i. e., on the opposite side thereof from theinterior of the furnace, and having a central passage into which thepowdered fuel is fed by an axially disposed nozzle I4. The nozzlecommunicates with a conduit connected with a source of fuel-supply andit has `a constricted throat within the passage of the tip. 'I'he nozzleis supported in a shell I5 which is fitted and secured interiorly of theblock and extends beyond the outer end thereof. The shell has at itsexterior end, an inwardly ranged ange I B, interiorly threaded toreceive the nozzle which has an exterior screw thread co-operating withthe other. By these means, the position of the nozzle inside thebody-member of the burner may be lengthwise adjusted, in accordance withdiffering conditions.

At the end of the shell inside the tip I3, is an inwardly extendingflange I1 for the support of a whirler 28, which may consist of a fixeddisk having radial, angularly bent vanes, between which thefuel-carrying currents must pass to enter the furnace. 'I'he whirlerfunctions as a means for reducing the velocity of the air currents andadditionally as an element to effect an intimate intermixture of thefuel and the air.

The passage of the body-member I3. at the inner end thereof, aresoutwardly from the whirler for the expansion of the currents, and it isdesirable that the are of the said passage be substantially in line withthat of the inner portion of the opening 8 of the preliminary combustionchamber. 'I'he faces of the terra cotta block other than those engagedby the metal parts I2 and I5, are preferably glazed to better resist thedetrimental influence of the heat of the furnace.

In the flaring inner end of the passage of the burner tip, are twoelectrodes I8 spaced apart to form a spark-gap I9. 'I'he electrodesextend through openings 20 in the block, which at the outer portion ofthe same are enlarged to contain terminal blocks 2| by which theelectrodes are connected to the leads 22 of a conveniently locatedsource of electricity.

'I'he electrodes are made of heat-resisting wire, such as chromiumnickel, and they are by means of the leads, connected with a source ofhigh tension electric current of perhaps from 10,000 to 12,000 volts, asmall standard transformer being included in the circuit.

'I'he wires and the terminal blocks are cemented in the holes of theblock, by means of suitable fillers and the binding-screws of theterminal blocksare accessible from the outside of the tip throughtransverse openings 23. The flanged outer end of the shell Ii has aseries of holes 25 for the admission of auxiliary air to the passage ofthe-burner-block, and the volume of this auxiliary air is controlled bya rotary damper 2l having holes .to register with those of the flange.

The preliminary combustionA chamber has at its underside a slot 26registering with an opening 6a in the furnace wall for the discharge ofashes and other solid products of combustion.

Having thus described the invention. its operation and the advantagesderived therein, will be apparent.

Air currents carrying pulverized fuel produced in a suitablegrindingmill, are forcibly fed to the burner, through the nozzle andthence pass through the whirler past the igniter, into the inner flaringportion 8 of the preliminary combustion chamber. The whirler, theoutward flare of the passage of the burner-tip in which the igniter isdisposed, and the outward nare of the inner portion 8 of the preliminarycombustion chamber, cooperate in reducing the velocity of the aircurrents, it being an important desideratum of the invention to, bythese means, produce the short flame essential in small furnaces such asthose used in residential heating-systems.

The heat-resisting burner-tip provides for the disposition of theelectrodes with perfect insulation and it forms a conical diffuser andexpander for the air currents as stated hereinbefore. The whirler byimparting 'a spinning motion to the air currents likewise effects theexpansion and consequent reduction in velocity of the same.

'I'he velocity of the air currents .entering the furnace is by theabove-described means reduced to a degree just suiiicient to keep thecoal-particles in suspension. Initially, the volatile hydrocarbons ofthe coal are ignited by the spark produced in the gap I9 between theelectrodes Il, it being understood that the air by which the coal iscarried, contains suiiicient oxygen to ignite said volatileconstituents.

Subsequently, the. heat produced byignition of the volatilehydrocarbons, ignites and burns the fixed carbons. usually with theassistance of the auxiliary supply of Aair drawn into the burner.through the damper-controlled openings 25 in the anges of the shell,and the space 3l between the burner tip and the preliminary combustionchamber.

At this time, the spark between the electrodes may be discontinued bybreaking the circuit in a suitable switch; it being obvious that afterthe fuel has once been ignited, the heat of the ignited parts thereof,is sumcient to support continued combustion.

In this manner, the fuel held in suspension by the air-currents, is putin a state of combustion in the preliminary combustion chamber andbefore it enters the furnace: proper, thereby differentiatingl thepresent method from others in which ignition and subsequent combustionof the fuel takes place in the combustion chamber of the furnace above aburner.

It is an important feature of the present invention that the velocity ofthe fuel-carrying air currents is reduced so as to closely approach thecritical point between the forces of suspension and gravitation to whichthe fuel is subject during its movement into the furnace, or in otherwords, that the velocity of the air-currents entering the furnace, isjust sumcient to maintain the fuel in suspension, thereby producing theshort flame which, as stated hereinbefore, adapts the inventionparticularly for use in furnaces of limited dimensions.

The position of the nozzle with relation tothe whirler is readilyadjusted by turning the latter in the screw-threaded opening of theshell and by the use of interchangeable nozzles of different throatopenings, the velocity and the volume of the air-currents entering theburner through the nozzle are further regulated.

The velocity of the air currents in the burner should be enoughto insurethe maximum effect of the whirler, in .entering the currents into thepreliminary combustion chamber ata low velocity andin a whirling motion,it being apparent that the preliminary combustion chamber provides thearea of preliminary combustion as stated hereinbefore, prior to asubstantially complete combustion of the fixed carbons of the fuel inthe furnace.

'I'he burner-tip is spaced from the preliminary combustion chamber, asshownat 3l, for cooling purposes and incidentally for the controllablevsupply of auxiliary air to the preliminary combustion chamber as may berequired to support combustion, it being understood that the width ofthe space may be varied by changing the thickness of washers IIa betweenthe parts I2 and l.

What I claim and desire to secure by Letters Patent is:

1. A burner system for furnaces, comprising a nozzle, a chamber toreceive and spread fuelcarrying air-currents discharging from thenozzle, a preliminary combustion chamber communicating with thefirst-mentioned chamber, a whirler separating the chambers and providinga passage therebetween, the preliminary combustion chamber providing anexpansion space for fuelcarrying currents entering therein, means forigniting fuel in the latter chamber, and means for the supply ofadditional air to said chamber to aid combustion and to effect thepassage therethrough ofthe ignited material for delivery to the furnaceat a reduced velocity.

2. In a burner unit for furnaces, a burner tip comprising a body ofrefractory material having a passage for fuel-carrying air currents, andhaving in its wall around said passage, openings Y for the placement ofelectrodes in opposed relation to each other within the passage toprovide a spark-gap, the openings being enlarged at their outer ends tocontain terminal blocks at the ends of the electrodes, and theenlargements having lateral entrances aifording access to the terminalblocks.

3. A furnace having a wall, a hollow block of refractory material in anopening of said wall providing a preliminary combustion chamber, a-

burner tip having an inwardly flaring' passage, rearwardly of and incommunication with said preliminary combustion chamber, a nozzle for theintroduction of fuel-carrying air-currents into the flaring passage ofthe burner tip, and means for igniting fuelin said air-currents, withinthe haring passage, prior to their entrance into the preliminarycombustion chamber and means between the flaring passage and thepreliminary combustion chamber for supplying atmospheric air to thepreliminary combustion chamber.

4. A furnace having a wall, a hollow block of refractory material in anopening of said wall providing an inwardly flaring preliminarycombustion chamber, a burner tip having an inwardly flaring passage,rearwardly of and in communication with said preliminary combustionchamber, a nozzle for the introduction of fuel-carrying air currentsinto the aring passage of the burner tip, and means for igniting fuel insaid air-currents, within the aring passage, prior to their entranceinto the preliminary combustion chamr.

5. A furnace having a wall, a hollow block of 'refractory material in anopening of said wall providing a preliminary combustion chamber, aburner tip having an inwardly flaring passage, rearwardly of and incommunication with said preliminary combustion chamber, a nozzle for theintroduction of fuel-carrying air-currents into the aring passage of theburner tip, a whirler to impart a whirling motion to the air-currentsentering the iiaring passage, and means for igniting fuel in saidair-currents, within the flaring passage, prior to their entrance intothe preliminary combustion chamber.

6. A furnace having a wall, a hollow. block of refractory material in anopening of said wall providing a preliminary combustion chamber, a

burner tip having an inwardly flaring passage, rearwardly of and incommunication with said preliminary combustion chamber, a nozzle for theintroduction of fuel-carrying air-currents into the flaring passage ofthe burner tip, and means for igniting fuel in said air-currents, withinthe naring passage, prior to their entrance into the preliminarycombustion chamber, there being. an entrance for secondary air into thepreliminary combustion chamber.

'7. A furnace having a wall, a hollow block of refractory material in anopening of said wall, providing a preliminary combustion chamber, aburner tip having an inwardly flaring passage, rearwardly of and incommunication with said preliminary combustion chamber, a nozzle for theintroduction of fuel-carrying air-currents into the flaring passage ofthe burner tip, and means for igniting fuel in said air-currents, withinthe flaring passage, prior to their entrance into the preliminarycombustion chamber, there being an entrance for secondary air into thepreliminary combustion chamber, around the burner tip.

8. A furnace having a wall, a hollow block of refractory material in anlopening of said wall, providing a preliminary combustion chamber, aburner tip having an inwardly flaring passage, rearwardly of and incommunication with said preliminary combustion chamber, a nozzle for theintroduction of fuel-carrying air currents into the flaring passage ofthe burner tip including a shell provided with an inlet for air, andmeans for igniting fuel in said air-currents, within the flaringpassage, prior to their entrance into the preliminary combustionchamber.

9. A furnace having a wall, a hollow block of refractory material in anopening of said wall, providing a preliminary combustion chamber, aburner tip having an inwardly aring passage, rearwardly of and incommunication with s aid preliminary combustion chamber, a nozzle forthe introduction of fuel-carrying air-currents into the aring passage ofthe burner tip including a shell provided with an inlet for air, awhirler in the shell to impart a whirling motion to the aircurrents, andmeans for igniting fuel in said aircurrents, Within the flaring passage,prior to their entrance into the preliminary combustion chamber.

10. The combination with a furnace, of a preliminary combustion chamber,having an opening therethrough, the walls of which are in oppositedirections from a transverse plane through the burner to provide aportion arlng toward the exterior of the furnace and a portion flaringto the interior thereof, a hollow burner tip positioned in the exteriorflaring portion, in spaced relation to the walls thereof, whereby toprovide an inlet for atmospheric air between the tip and said walls, theinterior hollow portion of said burner tip being flaredin the generaldirection of the flare of the walls of said interior aring portion,means to direct fuel-carrying currents into the flaring portion of theburner tip, and means in the burner tip to ignite incoming fuel carriedby said currents, prior to the passage thereof through the preliminarycombustion chamber, whereby said fuel will be delivered to the furnacein a state of combustion.

DURBIN VAN LAW.

